A5011594887- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- Pulsars and Gravitational Waves Research
- Advanced Mathematical Theories and Applications
- Atmospheric and Environmental Gas Dynamics
- CCD and CMOS Imaging Sensors
- Medical Imaging Techniques and Applications
- Astronomical and nuclear sciences
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Optical Imaging and Spectroscopy Techniques
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy and Laser Applications
- Cosmology and Gravitation Theories
- Spectroscopy and Chemometric Analyses
- Space Exploration and Technology
- Atmospheric Ozone and Climate
Museu de Astronomia e Ciências Afins
2021-2024
Universidade de São Paulo
2021-2024
University of Chicago
2023-2024
Instituto de Geofísica y Astronomía
2023-2024
Netherlands Institute for Radio Astronomy
2024
Electronics for Imaging (United States)
2024
Weatherford College
2021
Abstract We report the discovery and spectroscopic confirmation of an ultra-faint Milky Way satellite in constellation Leo. This system was discovered as a spatial overdensity resolved stars observed with Dark Energy Camera (DECam) data from early version third release DECam Local Volume Exploration (or DELVE) survey. The low luminosity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mi>V</mml:mi>...
We combine spectroscopic, photometric, and astrometric information from APOGEE data release 17 $Gaia$ early 3 to perform a self-consistent characterization of $Gaia$-Sausage/Enceladus (GSE), the remnant last major merger experienced by Milky Way, considering stars globular clusters (GCs) altogether. Our novel set chemodynamical criteria select genuine GSE yields metallicity distribution function with median [Fe/H] $-1.22$ dex $0.23$ dispersion. Stars present an excess [Al/Fe] [Mg/Mn] (also...
ABSTRACT The current and next observation seasons will detect hundreds of gravitational waves (GWs) from compact binary systems coalescence at cosmological distances. When combined with independent electromagnetic measurements, the source redshift be known, we able to obtain precise measurements Hubble constant H0 via distance–redshift relation. However, most observed mergers are not expected have counterparts, which prevents a direct measurement. In this scenario, one possibility is use...
Abstract We present the discovery of Aquarius III, an ultra-faint Milky Way satellite galaxy identified in second data release DECam Local Volume Exploration survey. Based on deeper follow-up imaging with DECam, we find that III is a low-luminosity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mi>V</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:msubsup> <mml:mn>2.5</mml:mn>...
Abstract We analyze the dynamical properties of ∼1500 very metal-poor (VMP; [Fe/H] ≲ −2.0) halo stars, based primarily on medium-resolution spectroscopic data from HK and Hamburg/ESO surveys. These data, collected over past 30 yr, are supplemented by a number calibration stars other small samples, along with astrometric information Gaia DR2. apply clustering algorithm to 4D energy-action space sample, identify set 38 dynamically tagged groups (DTGs), containing between 5 member stars. Many...
ABSTRACT We present the first detailed chemical-abundance analysis of stars from dwarf-galaxy stellar stream Wukong/LMS-1 covering a wide metallicity range ($-3.5 \lt \rm [Fe/H] \lesssim -1.3$). find abundance patterns that are effectively indistinguishable bulk Indus and Jhelum, pair smaller streams proposed to be dynamically associated with Wukong/LMS-1. confirmed carbon-enhanced metal-poor star ($\rm [C/Fe] \gt +0.7$ $\rm \sim -2.9$) in strong enhancements Sr, Y, Zr, which is peculiar...
Orbital characteristics based on Gaia Early Data Release 3 astrometric parameters are analyzed for ${\sim} 4000$ metal-poor stars ([Fe/H] $\leq -0.8$) compiled from the Best $\&$ Brightest survey. Selected as candidates broadband near- and far-IR photometry, $43\%$ of these had medium-resolution ($1200 \lesssim R 2000$) validation spectra obtained over a seven-year campaign $2014$ to $2020$ with variety telescopes. The remaining were chosen photometric metallicity determinations Huang et al....
We present deep optical observations of the stellar halo NGC 300, an LMC-mass galaxy, acquired with DEEP sub-component DECam Local Volume Exploration survey (DELVE) using 4 m Blanco Telescope. Our resolved star analysis reveals a large, low surface brightness stream ($M_{V}\sim-8.5$; [Fe/H] $= -1.4\pm0.15$) extending more than 40 kpc north from galaxy's center. also find other structures, including potentially additional wrap to south, which may be associated main stream. The morphology and...
We present deep Magellan$+$Megacam imaging of Centaurus I (Cen I) and Eridanus IV (Eri IV), two recently discovered Milky Way ultra-faint satellites. Our data reach $\sim2-3$ magnitudes deeper than the discovery from DECam Local Volume Exploration (DELVE) Survey. use these to constrain their distances, structural properties (e.g., half-light radii, ellipticity, position angle), luminosities. investigate whether systems show signs tidal disturbance, identify new potential member stars using...
Dwarf galaxies like Sagittarius (Sgr) provide a unique window into the early stages of galactic chemical evolution, particularly through their metal-poor stars. By studying abundances stars in Sgr core and tidal streams, we can gain insights assembly history this galaxy its heavy element nucleosynthesis processes. We efficiently selected extremely candidates streams for high-resolution spectroscopic analysis using metallicity-sensitive photometry from SkyMapper DR2, Gaia DR3 XP spectra...
The metal content of a galaxy's interstellar medium reflects the interplay between different evolutionary processes such as feedback from massive stars and accretion gas intergalactic medium. Despite expected abundance low-luminosity galaxies, low-mass low-metallicity regime remains relatively understudied. Since properties their resemble those early identifying objects in Local Universe is crucial to understand stages galaxy evolution. We used DR3 catalog Southern Photometric Survey...
Abstract We present deep optical observations of the stellar halo NGC 300, an LMC-mass galaxy, acquired with DEEP subcomponent DECam Local Volume Exploration survey using 4 m Blanco Telescope. Our resolved star analysis reveals a large, low surface brightness stream ( M V ∼ −8.5; [Fe/H] = −1.4 ± 0.15) extending more than 40 kpc north from galaxy’s center. also find other structures, including potentially additional wrap to south, which may be associated main stream. The morphology and...
Abstract In the first billion years after its formation, Galaxy underwent several mergers with dwarf satellites of various masses. The debris Gaia-Sausage/Enceladus (GSE), galaxy responsible for last significant merger Milky Way, dominates inner halo and has been suggested to be progenitor both Hercules-Aquila Cloud (HAC) Virgo Overdensity (VOD). We combine SEGUE, APOGEE, Gaia, StarHorse distances characterize chemodynamical properties verify link between HAC, VOD, GSE. find that orbital...
ABSTRACT Very metal-poor stars ($\rm [Fe/H] \lt -2$) in the Milky Way are fossil records of early chemical evolution and assembly structure Galaxy. However, they rare hard to find. Gaia DR3 has provided over 200 million low-resolution (R ≈ 50) XP spectra, which provides an opportunity greatly increase number candidate stars. In this work, we utilize XGBoost classification algorithm identify ∼200 000 very star candidates. Compared past sample by about order magnitude, with comparable or...
Abstract We present a comprehensive recalibration of narrowband/medium-band and broadband photometry from the Southern Photometric Local Universe Survey (S-PLUS) by leveraging two approaches: an improved Gaia XP synthetic (XPSP) method with corrected spectra, stellar color regression (SCR) Early Data Release 3 photometric data spectroscopic LAMOST 7. Through use millions stars as standards per band, we demonstrate existence position-dependent systematic errors, up to 23 mmag for main survey...
We identified 8 additional stars as members of the Helmi stream (HStr) in combined GALAH+ DR3 and $Gaia$ EDR3 catalog. By consistently reevaluating claimed from literature, we consolidate a sample 22 HStr with parameters determined high-resolution spectroscopy spanning considerably wider (by $\sim$0.5 dex) metallicity interval ($-2.5 \lesssim \rm[Fe/H] < -1.0$) than previously reported. Our study focuses on $\alpha$ (Mg Ca) neutron-capture (Ba Eu) elements. find that chemistry is typical...
We present the results of spectroscopic follow-up for 1897 low-metallicity star candidates, selected from Best & Brightest (B&B) Survey, carried out with GMOS-N/S (Gemini North/South telescopes) and Goodman (SOAR Telescope) spectrographs. From these low-resolution ($R \sim 2000$) spectra, we estimate stellar atmospheric parameters, as well carbon magnesium (representative $\alpha$ elements) abundance ratios. confirm that $56\%$ our program stars are metal-poor ([Fe/H] $< -1.0$), $30\%$ very...
In this work, we study the phase-space and chemical properties of Sagittarius (Sgr) stream, tidal tails produced by ongoing destruction Sgr dwarf spheroidal (dSph) galaxy, focusing on its very metal-poor (VMP; $\rm[Fe/H] < -2$) content. We combine spectroscopic astrometric information from SEGUE $Gaia$ EDR3, respectively, with data products a new large-scale run $\texttt{StarHorse}$ spectro-photometric code. Our selection criteria yields ${\sim}1600$ stream members, including ${>}200$ VMP...
ABSTRACT Milky Way globular clusters (GCs) display chemical enrichment in a phenomenon called multiple stellar populations (MSPs). While the mechanism is not fully understood, there correlation between cluster’s mass and fraction of enriched stars found therein. However, present-day GC masses are often smaller than their at time formation due to dynamical mass-loss. In this work, we explore relationship MSPs using stream 300S. We present abundances eight red giant branch member 300S with...
Metal-poor stars are key to our understanding of the early stages chemical evolution in Universe. New multi-filter surveys, such as Southern Photometric Local Universe Survey (S-PLUS), greatly advancing ability select low-metallicity stars. In this work, we analyse chemodynamical properties and ages 522 metal-poor candidates selected from S-PLUS data release 3. About 92% these were confirmed be ([Fe/H] $\leq -1$) based on previous medium-resolution spectroscopy. We calculated dynamical a...
In the cold dark matter paradigm, our Galaxy is predicted to contain >10000 subhaloes in $10^5-10^8M_\odot$ range which should be completely devoid of stars. Stellar streams are sensitive presence these subhaloes, can create small-scale features if they pass closely enough. Modelling encounters therefore, potentially recover subhalo's properties. this work, we demonstrate for generated numerical simulations, modelled on eccentric orbits a realistic Milky Way potential, includes Large...
This paper presents the first public data release of S-PLUS Ultra-Short Survey (USS), a photometric survey with short exposure times, covering approximately 9300 deg$^{2}$ Southern sky. The USS utilizes Javalambre 12-band magnitude system, including narrow and medium-band broad-band filters targeting prominent stellar spectral features. primary objective is to identify bright, extremely metal-poor (EMP; [Fe/H] $\leq -3$) ultra (UMP; -4$) stars for further analysis using medium-...
Abstract Neutron star mergers (NSMs) produce r -process elements after a time-delayed inspiral process. Once significant number of NSMs are present in galaxy, elements, such as Eu, expected to significantly increase with time. Yet, there have been limited observational data support Eu increasing within Local Group galaxies. We obtained high-resolution Magellan/MIKE observations 43 metal-poor stars the Gaia-Sausage/Enceladus (GSE) tidally disrupted galaxy −2.5 < [Fe/H] −1. For first time,...
Abstract The discovery of fast moving stars in Milky Way’s most massive globular cluster, ω Centauri ( Cen), has provided strong evidence for an intermediate-mass black hole (IMBH). However, Cen is known to be the stripped nuclear star cluster (NSC) ancient, now-destroyed, dwarf galaxy. best candidate original host progenitor tidally disrupted Gaia-Sausage/Enceladus (GSE), a former Way satellite as Large Magellanic Cloud. I compare Cen/GSE with other central BH hosts and place it within...